refactor: move brother_node development artifact to dev/test-nodes subdirectory

Development Artifact Cleanup:
✅ BROTHER_NODE REORGANIZATION: Moved development test node to appropriate location
- dev/test-nodes/brother_node/: Moved from root directory for better organization
- Contains development configuration, test logs, and test chain data
- No impact on production systems - purely development/testing artifact

✅ DEVELOPMENT ARTIFACTS IDENTIFIED:
- Chain ID: aitbc-brother-chain (test/development chain)
- Ports: 8010 (P2P) and 8011 (RPC) - different from production
- Environment: .env file with test configuration
- Logs: rpc.log and node.log from development testing session (March 15, 2026)

✅ ROOT DIRECTORY CLEANUP: Removed development clutter from production directory
- brother_node/ moved to dev/test-nodes/brother_node/
- Root directory now contains only production-ready components
- Development artifacts properly organized in dev/ subdirectory

DIRECTORY STRUCTURE IMPROVEMENT:
📁 dev/test-nodes/: Development and testing node configurations
🏗️ Root Directory: Clean production structure with only essential components
🧪 Development Isolation: Test environments separated from production

BENEFITS:
✅ Clean Production Directory: No development artifacts in root
✅ Better Organization: Development nodes grouped in dev/ subdirectory
✅ Clear Separation: Production vs development environments clearly distinguished
✅ Maintainability: Easier to identify and manage development components

RESULT: Successfully moved brother_node development artifact to dev/test-nodes/ subdirectory, cleaning up the root directory while preserving development testing environment for future use.

dev/env/node_modules/@openzeppelin/contracts/interfaces/draft-IERC6093.sol

@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/draft-IERC6093.sol)
+pragma solidity >=0.8.4;
+
+/**
+ * @dev Standard ERC-20 Errors
+ * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-20 tokens.
+ */
+interface IERC20Errors {
+    /**
+     * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
+     * @param sender Address whose tokens are being transferred.
+     * @param balance Current balance for the interacting account.
+     * @param needed Minimum amount required to perform a transfer.
+     */
+    error ERC20InsufficientBalance(address sender, uint256 balance, uint256 needed);
+
+    /**
+     * @dev Indicates a failure with the token `sender`. Used in transfers.
+     * @param sender Address whose tokens are being transferred.
+     */
+    error ERC20InvalidSender(address sender);
+
+    /**
+     * @dev Indicates a failure with the token `receiver`. Used in transfers.
+     * @param receiver Address to which tokens are being transferred.
+     */
+    error ERC20InvalidReceiver(address receiver);
+
+    /**
+     * @dev Indicates a failure with the `spender`’s `allowance`. Used in transfers.
+     * @param spender Address that may be allowed to operate on tokens without being their owner.
+     * @param allowance Amount of tokens a `spender` is allowed to operate with.
+     * @param needed Minimum amount required to perform a transfer.
+     */
+    error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed);
+
+    /**
+     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
+     * @param approver Address initiating an approval operation.
+     */
+    error ERC20InvalidApprover(address approver);
+
+    /**
+     * @dev Indicates a failure with the `spender` to be approved. Used in approvals.
+     * @param spender Address that may be allowed to operate on tokens without being their owner.
+     */
+    error ERC20InvalidSpender(address spender);
+}
+
+/**
+ * @dev Standard ERC-721 Errors
+ * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-721 tokens.
+ */
+interface IERC721Errors {
+    /**
+     * @dev Indicates that an address can't be an owner. For example, `address(0)` is a forbidden owner in ERC-20.
+     * Used in balance queries.
+     * @param owner Address of the current owner of a token.
+     */
+    error ERC721InvalidOwner(address owner);
+
+    /**
+     * @dev Indicates a `tokenId` whose `owner` is the zero address.
+     * @param tokenId Identifier number of a token.
+     */
+    error ERC721NonexistentToken(uint256 tokenId);
+
+    /**
+     * @dev Indicates an error related to the ownership over a particular token. Used in transfers.
+     * @param sender Address whose tokens are being transferred.
+     * @param tokenId Identifier number of a token.
+     * @param owner Address of the current owner of a token.
+     */
+    error ERC721IncorrectOwner(address sender, uint256 tokenId, address owner);
+
+    /**
+     * @dev Indicates a failure with the token `sender`. Used in transfers.
+     * @param sender Address whose tokens are being transferred.
+     */
+    error ERC721InvalidSender(address sender);
+
+    /**
+     * @dev Indicates a failure with the token `receiver`. Used in transfers.
+     * @param receiver Address to which tokens are being transferred.
+     */
+    error ERC721InvalidReceiver(address receiver);
+
+    /**
+     * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
+     * @param operator Address that may be allowed to operate on tokens without being their owner.
+     * @param tokenId Identifier number of a token.
+     */
+    error ERC721InsufficientApproval(address operator, uint256 tokenId);
+
+    /**
+     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
+     * @param approver Address initiating an approval operation.
+     */
+    error ERC721InvalidApprover(address approver);
+
+    /**
+     * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
+     * @param operator Address that may be allowed to operate on tokens without being their owner.
+     */
+    error ERC721InvalidOperator(address operator);
+}
+
+/**
+ * @dev Standard ERC-1155 Errors
+ * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-1155 tokens.
+ */
+interface IERC1155Errors {
+    /**
+     * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
+     * @param sender Address whose tokens are being transferred.
+     * @param balance Current balance for the interacting account.
+     * @param needed Minimum amount required to perform a transfer.
+     * @param tokenId Identifier number of a token.
+     */
+    error ERC1155InsufficientBalance(address sender, uint256 balance, uint256 needed, uint256 tokenId);
+
+    /**
+     * @dev Indicates a failure with the token `sender`. Used in transfers.
+     * @param sender Address whose tokens are being transferred.
+     */
+    error ERC1155InvalidSender(address sender);
+
+    /**
+     * @dev Indicates a failure with the token `receiver`. Used in transfers.
+     * @param receiver Address to which tokens are being transferred.
+     */
+    error ERC1155InvalidReceiver(address receiver);
+
+    /**
+     * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
+     * @param operator Address that may be allowed to operate on tokens without being their owner.
+     * @param owner Address of the current owner of a token.
+     */
+    error ERC1155MissingApprovalForAll(address operator, address owner);
+
+    /**
+     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
+     * @param approver Address initiating an approval operation.
+     */
+    error ERC1155InvalidApprover(address approver);
+
+    /**
+     * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
+     * @param operator Address that may be allowed to operate on tokens without being their owner.
+     */
+    error ERC1155InvalidOperator(address operator);
+
+    /**
+     * @dev Indicates an array length mismatch between ids and values in a safeBatchTransferFrom operation.
+     * Used in batch transfers.
+     * @param idsLength Length of the array of token identifiers
+     * @param valuesLength Length of the array of token amounts
+     */
+    error ERC1155InvalidArrayLength(uint256 idsLength, uint256 valuesLength);
+}